1. Field of the Invention
The present invention relates to a method of manufacturing ceramic electronic parts, in particular to a method of manufacturing ceramic electronic parts each including ceramic layers and internal electrodes formed with the use of an electrophotography technique.
2. Description of the Related Art
Ceramic electronic parts such as a laminated capacitor, a laminated inductor, a laminated LC filter, and a multi-layered ceramic substrate, may be manufactured by laminating a plurality of green sheets, followed by sintering these laminated green sheets. In practice, each of the green sheets is formed by mixing and kneading together a ceramic powder, a binder, a plasticizer agent, and an organic solvent to obtain a paste-like material which is then formed into a plate-like piece having a predetermined thickness, followed by a drying treatment. In more detail, each green sheet has several electrode patterns formed by using a screen printing treatment so as to obtain a plurality of desired internal electrodes.
An example of a method of manufacturing the ceramic electronic parts, is a green sheet laminating method which comprises a step of forming a plurality of via holes through a plurality of ceramic green sheets, a step of printing electrode patterns on the ceramic green sheets using an electrically conductive paste as a printing material by virtue of screen printing treatment, a step of laminating together the above ceramic green sheets after having been treated in the above steps, and a step of sintering the laminated ceramic green sheets.
FIG. 7 is an exploded sectional view schematically indicating a multi-layered ceramic substrate produced by a green sheet laminating method which is a conventional manufacturing method according to a prior art. As shown in FIG. 7, the multi-layered ceramic substrate 70 is comprised of a plurality of ceramic green sheets 711-713. The ceramic green sheets 711 and 712 have desired internal electrodes 721, 722 formed on the inner sides thereof. Further, the ceramic green sheet 712 has a plurality of via hole electrodes 73 each formed through the ceramic green sheet. Then, the internal electrodes 721 and 722 of the ceramic green sheets 711 and 712 are mutually connected by way of via hole electrodes 73, so that they are electrically contacted with one another. In this manner, the multi-layered ceramic substrate 70 serves to form one kind of an electric circuit.
However, there are some problems associated with the above-discussed conventional method of manufacturing ceramic electronic parts. Namely, when the screen printing method is used to produce electrode patterns which will then be formed into a plurality of internal electrodes or external electrodes, it is necessary to at first prepare a special mask having a predetermined design corresponding to the electrode patterns to be formed. In particular, when manufacturing some multi-layered ceramic substrates which are likely to involve many kinds or types but are required to be produced only in a small amount, it is necessary to employ many kinds of specific masks, resulting in a problem that a relatively long time is needed to prepare these special masks, and hence causing an increase in a cost of manufacturing the multi-layered ceramic substrate.
Another problem with the above-discussed conventional method of manufacturing ceramic electronic parts is that if some internal electrodes or external electrodes are needed to be changed, it is necessary that some special masks which have already been made have to be modified in order to form desired electrode patterns for obtaining desired internal electrodes or desired external electrodes. Accordingly, the special masks for use in the above conventional method are not universal and thus they are not convenient in view of an industrial purpose.